tire size RAM CHASSIS CAB 2017 User Guide

Tire Terminology And Definitions
Term Definition
B-Pillar The vehicle B-Pillar is the structural member of the body located be-
hind the front door.
Cold Tire Inflation Pressure Cold tire inflation pressure is defined as the tire pressure after the
vehicle has not been driven for at least three hours, or driven less
than 1 mile (1.6 km) after sitting for a minimum of three hours. In-
flation pressure is measured in units of PSI (pounds per square inch)
or kPa (kilopascals).
Maximum Inflation Pressure The maximum inflation pressure is the maximum permissible cold
tire inflation pressure for this tire. The maximum inflation pressure is
molded into the sidewall.
Recommended Cold Tire Inflation Pressure Vehicle manufacturer’s recommended cold tire inflation pressure as
shown on the tire placard.
Tire Placard A label permanently attached to the vehicle describing the vehicle’s
loading capacity, the original equipment tire sizes and the recom-
mended cold tire inflation pressures.370 STARTING AND OPERATING

WARNING! (Continued)Over-inflation reduces a tire’s ability to cushion
shock. Objects on the road and chuck holes can cause
damage that results in tire failure. Unequal tire
pressures can cause steering problems. You could
lose control of your vehicle. Over-inflated or under-
inflated tires can affect vehicle handling and can fail
suddenly, resulting in loss of vehicle control. Always
drive with each tire inflated to the recommended
cold tire inflation pressure. Tire And Loading Information Placard
This placard tells you important information about the:
1. Number of people that can be carried in the vehicle.
2. Total weight your vehicle can carry.
3. Tire size designed for your vehicle.
4. Cold tire inflation pressures for the front, rear, and spare
tires. Tire And Loading Information Placard372 STARTING AND OPERATING

Loading
The vehicle maximum load on the tire must not exceed the
load carrying capacity of the tire on your vehicle. You will
not exceed the tire’s load carrying capacity if you adhere to
the loading conditions, tire size, and cold tire inflation
pressures specified on the Tire and Loading Information
placard in “Vehicle Loading” in “Starting And Operating”,
or the Tire Information Supplement, located in your Own-
er ’s Information kit.
NOTE: Under a maximum loaded vehicle condition, gross
axle weight ratings (GAWRs) for the front and rear axles
must not be exceeded. Refer to “Vehicle Loading” in
“Starting And Operating”, or the Tire Information Supple-
ment located in your Owner ’s Information kit, for further
information on GAWRs, vehicle loading, and trailer tow-
ing.
To determine the maximum loading conditions of your
vehicle, locate the statement “The combined weight of
occupants and cargo should never exceed XXX kg or
XXX lbs” on the Tire and Loading Information placard. The
combined weight of occupants, cargo/luggage and trailer
tongue weight (if applicable) should never exceed the
weight referenced here. Steps For Determining Correct Load Limit—
(1) Locate the statement “The combined weight of
occupants and cargo should never exceed XXX kg or
XXX lbs.” on your vehicle’s placard.
(2) Determine the combined weight of the driver and
passengers that will be riding in your vehicle.
(3) Subtract the combined weight of the driver and
passengers from XXX kg or XXX lbs.
(4) The resulting figure equals the available amount of
cargo and luggage load capacity. For example, if “XXX”
amount equals 1400 lbs. and there will be five 150 lb
passengers in your vehicle, the amount of available
cargo and luggage load capacity is 650 lbs. (1400-750
(5x150) = 650 lbs.)
(5) Determine the combined weight of luggage and
cargo being loaded on the vehicle. That weight may not
safely exceed the available cargo and luggage load
capacity calculated in Step 4.
(6) If your vehicle will be towing a trailer, load from
your trailer will be transferred to your vehicle. Consult
this manual to determine how this reduces the available
cargo and luggage load capacity of your vehicle. 5STARTING AND OPERATING 373

Damaged Run Flat tires, or Run Flat tires that have
experienced a loss of pressure should be replaced immedi-
ately with another Run Flat tire of identical size and service
description (Load Index and Speed Symbol).
Tire Types
All Season Tires — If Equipped
All season tires provide traction for all seasons (Spring,
Summer, Fall and Winter). Traction levels may vary be-
tween different all season tires. All season tires can be
identified by the M+S, M&S, M/S or MS designation on the
tire sidewall. Use all season tires only in sets of four; failure
to do so may adversely affect the safety and handling of
your vehicle.
Summer Or Three Season Tires — If Equipped
Summer tires provide traction in both wet and dry condi-
tions, and are not intended to be driven in snow or on ice.
If your vehicle is equipped with Summer tires, be aware
these tires are not designed for Winter or cold driving
conditions. Install Winter tires on your vehicle when am-
bient temperatures are less than 40°F (5°C) or if roads are
covered with ice or snow. For more information, contact an
authorized dealer. Summer tires do not contain the all season designation or
mountain/snowflake symbol on the tire sidewall. Use
Summer tires only in sets of four; failure to do so may
adversely affect the safety and handling of your vehicle.
WARNING!Do not use Summer tires in snow/ice conditions. You
could lose vehicle control, resulting in severe injury or
death. Driving too fast for conditions also creates the
possibility of loss of vehicle control.
Snow Tires
Some areas of the country require the use of snow tires
during the Winter. Snow tires can be identified by a
“mountain/snowflake” symbol on the tire sidewall.
If you need snow tires, select tires
equivalent in size and type to the origi-
nal equipment tires. Use snow tires only
in sets of four; failure to do so may
adversely affect the safety and handling
of your vehicle.
Snow tires generally have lower speed ratings than what
was originally equipped with your vehicle and should not
be operated at sustained speeds over 75 mph (120 km/h). 5STARTING AND OPERATING 379

Compact Spare Tire — If Equipped
The compact spare is for temporary emergency use only.
You can identify if your vehicle is equipped with a compact
spare by looking at the spare tire description on the Tire
and Loading Information Placard located on the driver ’s
side door opening or on the sidewall of the tire. Compact
spare tire descriptions begin with the letter “T” or “S”
preceding the size designation. Example: T145/80D18
103M.
T, S = Temporary Spare Tire
Since this tire has limited tread life, the original equipment
tire should be repaired (or replaced) and reinstalled on
your vehicle at the first opportunity.
Do not install a wheel cover or attempt to mount a
conventional tire on the compact spare wheel, since the
wheel is designed specifically for the compact spare tire.
Do not install more than one compact spare tire and wheel
on the vehicle at any given time. WARNING!Compact and Collapsible spares are for temporary
emergency use only. With these spares, do not drive
more than 50 mph (80 km/h). Temporary use spares
have limited tread life. When the tread is worn to the
tread wear indicators, the temporary use spare tire
needs to be replaced. Be sure to follow the warnings,
which apply to your spare. Failure to do so could result
in spare tire failure and loss of vehicle control.
Full Size Spare — If Equipped
The full size spare is for temporary emergency use only.
This tire may look like the originally equipped tire on the
front or rear axle of your vehicle, but it is not. This spare
tire may have limited tread life. When the tread is worn to
the tread wear indicators, the temporary use full size spare
tire needs to be replaced. Since it is not the same as your
original equipment tire, replace (or repair) the original
equipment tire and reinstall on the vehicle at the first
opportunity. 5STARTING AND OPERATING 381

WARNING!Tires and the spare tire should be replaced after six
years, regardless of the remaining tread. Failure to
follow this warning can result in sudden tire failure.
You could lose control and have a collision resulting in
serious injury or death.
Keep dismounted tires in a cool, dry place with as little
exposure to light as possible. Protect tires from contact with
oil, grease, and gasoline.
Replacement Tires
The tires on your new vehicle provide a balance of many
characteristics. They should be inspected regularly for
wear and correct cold tire inflation pressures. The manu-
facturer strongly recommends that you use tires equivalent
to the originals in size, quality and performance when
replacement is needed. Refer to the paragraph on “Tread
Wear Indicator” in this section. Refer to the Tire and
Loading Information placard or the Vehicle Certification
Label for the size designation of your tire. The Load Index
and Speed Symbol for your tire will be found on the
original equipment tire sidewall. See the Tire Sizing Chart example found in the “Tire Safety
Information” section of this manual for more information
relating to the Load Index and Speed Symbol of a tire.
It is recommended to replace the two front tires or two rear
tires as a pair. Replacing just one tire can seriously affect
your vehicle’s handling. If you ever replace a wheel, make
sure that the wheel’s specifications match those of the
original wheels.
It is recommended you contact your authorized tire dealer
or original equipment dealer with any questions you may
have on tire specifications or capability. Failure to use
equivalent replacement tires may adversely affect the
safety, handling, and ride of your vehicle.384 STARTING AND OPERATING

WARNING!• Do not use a tire, wheel size or rating other than that
specified for your vehicle. Some combinations of
unapproved tires and wheels may change suspen-
sion dimensions and performance characteristics,
resulting in changes to steering, handling, and brak-
ing of your vehicle. This can cause unpredictable
handling and stress to steering and suspension com-
ponents. You could lose control and have a collision
resulting in serious injury or death. Use only the tire
and wheel sizes with load ratings approved for your
vehicle.
• Never use a tire with a smaller load index or capacity,
other than what was originally equipped on your
vehicle. Using a tire with a smaller load index could
result in tire overloading and failure. You could lose
control and have a collision.
• Failure to equip your vehicle with tires having ad-
equate speed capability can result in sudden tire
failure and loss of vehicle control. CAUTION!Replacing original tires with tires of a different size
may result in false speedometer and odometer read-
ings.
TIRE CHAINS (TRACTION DEVICES)
Use of traction devices require sufficient tire-to-body clear-
ance. Follow these recommendations to guard against
damage.
• Traction device must be of proper size for the tire, as
recommended by the traction device manufacturer. 5STARTING AND OPERATING 385

Please follow the table below for proper tire size, chain
type, and axle recommendations:
Vehicle Axle
Recommenda-
tions Tire Sizes Chain Class
Chassis Cab 3500 (Single Rear Wheel) Models Rear Only LT265/70R18E U Class
Chassis Cab 3500 (Dual Rear Wheel) 4X2 Models Rear Only LT235/80R17E U Class
Chassis Cab 3500 (Dual Rear Wheel) 4X4 Models Front/Rear LT235/80R17E U Class
Chassis Cab 4500/5500 Models Rear Only 225/70R19.5G U Class
WARNING!Using tires of different size and type (M+S, Snow)
between front and rear axles can cause unpredictable
handling. You could lose control and have a collision.
CAUTION!To avoid damage to your vehicle or tires, observe the
following precautions:
• Because of restricted traction device clearance be-
tween tires and other suspension components, it is (Continued) CAUTION! (Continued)important that only traction devices in good condi-
tion are used. Broken devices can cause serious
damage. Stop the vehicle immediately if noise occurs
that could indicate device breakage. Remove the
damaged parts of the device before further use.
• Install device as tightly as possible and then re-
tighten after driving about ½ mile (0.8 km).
• Do not exceed 30 mph (48 km/h).
• Drive cautiously and avoid severe turns and large
bumps, especially with a loaded vehicle. (Continued)386 STARTING AND OPERATING

The TPMS will continue to warn the driver of low tire
pressure as long as the condition exists, and will not turn
off until the tire pressure is at or above the recommended
cold placard pressure. Once the low tire pressure warning
(Tire Pressure Monitoring [TPM] Telltale Light) illumi-
nates, you must increase the tire pressure to the recom-
mended cold placard pressure in order for the “Tire
Pressure Monitoring Telltale Light” to turn off. The system
will automatically update and the “Tire Pressure Monitor-
ing Telltale Light” will turn off once the system receives the
updated tire pressures. The vehicle may need to be driven
for up to 20 minutes above 15 mph (24 km/h) in order for
the TPMS to receive this information.
For example, your vehicle may have a recommended cold
(parked for more than three hours) placard pressure of 30
psi (207 kPa). If the ambient temperature is 68°F (20°C) and
the measured tire pressure is 27 psi (186 kPa), a tempera-
ture drop to 20°F (-7°C) will decrease the tire pressure to
approximately 23 psi (158 kPa). This tire pressure is suffi-
ciently low enough to turn ON the “Tire Pressure Moni-
toring Telltale Light.” Driving the vehicle may cause the
tire pressure to rise to approximately 27 psi (186 kPa), but
the “Tire Pressure Monitoring Telltale Light” will still be
ON. In this situation, the “Tire Pressure Monitoring Telltale Light” will turn OFF only after the tires are inflated to the
vehicle’s recommended cold placard pressure value.
CAUTION!• The TPMS has been optimized for the original
equipment tires and wheels. TPMS pressures and
warning have been established for the tire size
equipped on your vehicle. Undesirable system op-
eration or sensor damage may result when using
replacement equipment that is not of the same size,
type, and/or style. Aftermarket wheels can cause
sensor damage.
• Using aftermarket tire sealants may cause the Tire
Pressure Monitoring System (TPMS) sensor to be-
come inoperable. After using an aftermarket tire
sealant it is recommended that you take your vehicle
to an authorized dealership to have your sensor
function checked.
• After inspecting or adjusting the tire pressure always
reinstall the valve stem cap. This will prevent mois-
ture and dirt from entering the valve stem, which
could damage the TPMS sensor. 5STARTING AND OPERATING 391

NOTE:
• The TPMS is not intended to replace normal tire care and
maintenance or to provide warning of a tire failure or
condition.
• The TPMS should not be used as a tire pressure gauge
while adjusting your tire pressure.
• Driving on a significantly under-inflated tire causes the
tire to overheat and can lead to tire failure. Under-
inflation also reduces fuel efficiency and tire tread life,
and may affect the vehicle’s handling and stopping
ability.
• The TPMS is not a substitute for proper tire mainte-
nance, and it is the driver ’s responsibility to maintain
correct tire pressure using an accurate tire pressure
gauge, even if under-inflation has not reached the level
to trigger illumination of the “Tire Pressure Monitoring
Telltale Light.”
• Seasonal temperature changes will affect tire pressure,
and the TPMS will monitor the actual tire pressure in the
tire. Base System — If Equipped
The Tire Pressure Monitor System (TPMS) uses wireless
technology with wheel rim mounted electronic sensors to
monitor tire pressure levels. Sensors mounted to each
wheel as part of the valve stem transmit tire pressure
readings to the receiver module.
NOTE: It is particularly important for you to check the tire
pressure in all of the tires on your vehicle monthly and to
maintain the proper pressure.
The TPMS consists of the following components:
• Receiver module
• Four TPM sensors
• TPM Telltale Light
The matching full size spare wheel and tire assembly (if
equipped) has a TPM sensor. The matching full size spare
can be used in place of any of the four road tires. The TPMS
will only monitor the pressure in the full size spare when
it is used in place of a road tire. Otherwise, a spare with a
pressure below the low-pressure limit will not cause the
“Tire Pressure Monitoring Telltale Light” to illuminate or
the chime to sound.392 STARTING AND OPERATING